Bruchhauser Steine natural monument

Geology: The four Bruchhauser Steine—which reach heights of up to 92 meters (Bornstein, Goldstein, Ravenstein, and Feldstein)—are among the most impressive geological features in the Hochsauerland region and the entire Rhenish Slate Mountains. They bear witness to a massive volcanic eruption on the floor of the Devonian sea approximately 390 million years ago. They consist of the very hard volcanic extrusive rock quartz porphyry (rhyolite) with inclusions of the minerals quartz and feldspar and mark the remains of a volcanic vent that penetrated the marine sediments of that time. Over the following millions of years, the deposits were folded into a mountain range and slowly sculpted out of their softer Devonian clay shale matrix through weathering processes. In the process, the weathering-resistant volcanic rocks were largely preserved as “hard cores.” Further evidence of erosion is provided by the extensive boulder fields containing chunks of quartz porphyry below the rock complexes along the L 743 south of the village of Olsberg-Elleringhausen.

However, the Bruchhauser Steine are not only a geologically rewarding field trip destination. As a refuge for arctic-alpine plants, they are among the rare habitats of plants—so-called “relict species”—from the Ice Age that are no longer native to our region. Only here—under extreme climatic conditions—have they been able to survive to this day and have not been displaced by plants from warmer periods. The “Bruchhauser Steine” are home to significant plant populations (Alpine goosefoot, hawkweed with lotus-like leaves) as well as a peregrine falcon nesting site.

Age of the rocks: quartz porphyry (rhyolite): Middle Devonian, Eifel Stage (approximately 390 million years ago)
In April 2017, the Bruchhauser Steine were designated a National Natural Monument—the first in North Rhine-Westphalia.

In 2006, the Bruchhauser Steine were awarded the designation “National Geotope” by the Academy of Geosciences in Hanover (Akademie der Geowissenschaften zu Hannover e.V.).

Holiday opening hours: During the Christmas break, the Bruchhauser Steine are open daily from 11:00 a.m. to 4:00 p.m. During the Easter break, the Bruchhauser Steine are open daily from 10:00 a.m. to 4:00 p.m.
If a holiday falls on a Monday, the Bruchhauser Steine are also open on that day.